Bogging under acceleration
Bogging under acceleration
Hey everyone, I've been chasing an issue with my firebird for almost two years now. I can idle (it's sporadic) and accelerate (but I have to be slow, if I stomp on it from idle it'll bog and then choppily climb in revs). I also have starting issues, I have to feather the throttle for it to settle at idle. I've replaced the tps (and set it to the correct voltage and verified that it climbs linearly) and put bosch 3's in trying to chase this. It definitely runs better than it did before, but nowhere near "normal". It idles ok and wont die on its own. When i stomp on it theres a sort of "spelunking" noise that comes from the intake and a sudden increase in intake suction that quickly drops as it bogs. After the bogging it'll climb in revs but it's choppy. Does this seem more like a vacuum leak issue or a fuel starvation issue? The only fuel component left to replace is the fuel pump itself... but if it's not the problem I'm not trying to drop the whole rear end of the car lol. Any tips would be appreciated, it seems sort of like what Kincer described in recent posts, but different enough that I'd love some help. Thanks!
Member
Joined: Jun 2020
Posts: 189
Likes: 98
From: Western Pa
Car: 1989 Trans Am
Engine: 305 H.O. TPI
Transmission: Auto 700R4
Axle/Gears: 3.42 posi
Re: Bogging under acceleration
Hey everyone, I've been chasing an issue with my firebird for almost two years now. I can idle (it's sporadic) and accelerate (but I have to be slow, if I stomp on it from idle it'll bog and then choppily climb in revs). I also have starting issues, I have to feather the throttle for it to settle at idle. I've replaced the tps (and set it to the correct voltage and verified that it climbs linearly) and put bosch 3's in trying to chase this. It definitely runs better than it did before, but nowhere near "normal". It idles ok and wont die on its own. When i stomp on it theres a sort of "spelunking" noise that comes from the intake and a sudden increase in intake suction that quickly drops as it bogs. After the bogging it'll climb in revs but it's choppy. Does this seem more like a vacuum leak issue or a fuel starvation issue? The only fuel component left to replace is the fuel pump itself... but if it's not the problem I'm not trying to drop the whole rear end of the car lol. Any tips would be appreciated, it seems sort of like what Kincer described in recent posts, but different enough that I'd love some help. Thanks!
Re: Bogging under acceleration
It's been a minute... finally back from school long enough to work on the car. Fuel gauge hooked up. Key in "ON" position yields 10-15 psi! Should be between 42-47 right?? Seems like a Fuel pump change should be in order right?
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Joined: Feb 2021
Posts: 1,208
Likes: 449
From: WA
Car: 1989 IROC-Z
Engine: L98 350 TPI
Transmission: 700R4
Axle/Gears: BW 9 Bolt / 2.77 Posi
Re: Bogging under acceleration
More like 38-43 psi, but yeah if it isn't getting close to that then you most likely have a dying fuel pump.
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Joined: Jul 1999
Posts: 1,556
Likes: 28
From: Adrian, Mi, USA
Car: 1988 Pontiac Firebird Formula
Engine: 5.7 TPI
Transmission: 700R4
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